Rsj beam help before I can move on...

[Davidiman25]

Hi guys

I'm new here and need some help.

Building a kitchen extension and had architect draw up plans as well as the structural engineer do the calls, I was literally about to start building up to DPC and then notice on the plans ip the structural engineer has written instructions to support the rsj as '500x250x300 do concrete pads cast in existing cavity wall below DPC, central under posts; if wall is adequate - otherwise bolt staunchons to foundations.

A) were not sure what he means does he mean we need to have a slap below DPC? If so why? Normally just goes on padstones?

B) how do we know if the wall is adequate? The old foundations are all good so do we need to do more?

Any help greatly appreciated.

 

[Davidiman25]

Someone please reply

 

[tony1851]

It's not clear from your post what structure the SE has designed. Is it just a beam, or is it a moment frame (aka 'goal post') with steel columns either side?
How wide is the structural opening? It could be that you don't really need steel columns if you have sufficient brickwork left.

 

[Davidiman25]

Pix below hopefully can help

Architect drawings

• Davidiman25
• 30 Jun 2013
• 1

Structural engineer

• Davidiman25
• 30 Jun 2013
• 1

Structural engineer pg 2

• Davidiman25
• 30 Jun 2013
• 1

 

[tony1851]

It looks as though he has designed you a frame for lateral stability. This has to be firmly fixed at below ground level, and casting a concrete pad is one way.

Can't see clearly from the drawing what the baseplate size is, but the size given for your pad seems a bit on the small side, bearing in mind that you have to cast holding-down bolts into this to fix the bottom plate of the upright.

An easier way might be to use a steel ground beam laid directly on top of the existing foundation, and bolt the stanchions to that, but you would need to speak to your SE to confirm this.

 

[Davidiman25]

Thank you so much waiting to hear back from SE will be hearing tomorrow. Does the installation of the uprights either bolted to the concrete pads or foundations affect staying the block work up to DPC?

 

[Davidiman25]

Starting not staying

 

[tony1851]

Does the installation of the uprights either bolted to the concrete pads or foundations affect staying the block work up to DPC?

That would do. Even though it might mean a delay, I would be inclined to wait until you have spoken with the SE before going further. Could be wasted work otherwise?